Quoting Pavel Zubkou (pavel.zubkou@gmail.com):
> Package: debian-installer
> Severity: wishlist
>
> Using Squeeze installer RC2 (text mode via "Install" option from boot menu), after selecting "Guided, entire disk, encrypted LVM" as a partitioning mode and confirming it, there is a long process of erasing data from partition #5.
>
> As I am installing Debian on a new system with a blank disk it will be prefered to omit "Erasing data" step by telling installer not to do it, because it is time-consuming and obviously not needed on a new disk.
You can. Just "hit" Cancel when the erase progress bar is showing
up. It will cancel the erase process and things will continue.
At least, this is what happened during a short test I just did.